Sound conduit for sound-recording and sound-reproducing instruments



March 27, 1928. 1,663,906

E. FINKING SOUND CONDUIT FOR SOUND RECORDING AND SOUND REPRODUCING INSTRUMENTS F1196 Aug. 17. 1926 Patented Mar. 127, 1928.

UNITED STATES PATENT: OFFICE.

ERNST FINKING, OF LEIIZIG, GERMANY.

SOUND CONDUIT FOR SOUND-RECORDING AND SOUND-REPRODUCING INSTRUMENTS.

Application fiied August 17, 1926, Serial No. 129,848, and in Germany Apill 9, 1925.

My invention relates to improvements in 'sound conduits for sound recording and sound reproducing instruments.

With sound reproducing instruments considerable distortion is liable to occur in the reproduction of certain sounds, more particularly musical notes. The notes of'a. violin, when reproduced, approximate to those of a flute, and so on, the worst example being, probably, that of the bugle and trumpet. Even with the human voice the characteristic personal inflexion is largeL lost. This distortionor blurring is largely due to the metal walls of the sound tubes which vibrate and producenotes of their own thus'creating secondary noises and in part overlaying the music or speech. Another cause of the defect-is the rigidity of the joints in the soundbox connections, causing the scratching of the needle, vibrations of the room, and vibrations of the motor to be transmitted.

According to my invention the metal sound conduit leading from the sound box is interrupted in several places by connectors of elastic material, for example rubber, and these connectors may be used at the parts where the tube and horn or flare are supported by the cabinet, panel or frame, so that they constitute elastic bearings.

An example of apparatus according to my invention is shown in the annexed drawing, partly in section.

In this example the sound conduit comprises a tone arm on, a tube a, and a horn or flare. e. The sound boxf is joined to the tone-arm in known manner by a rubber connector 7), and-the tone arm is connected to the tube an by a ball joinhg and rubber c'onnector 6. Another rubber connector I), is provided between the tube a and the horn e. The connectors are so disposed that thereis no contact between the metal parts which joint 9 may also be covered with rubber, so that at this joint also there is no metallic contact with the tone arm. In order to insure that no metal part ofthe conduit is in contact with the casing h of the instrument, theconnectors b and b, are placed at the parts Where the conduit is supported by the casing. For the same reason the free end of the flare e is held in place by two rubber rings 2'', which are fastened at the upper wall of the casing around the sound-hole.

Instead of rubber any other elastic material adapted to absorb vibration may be used. The elastic connectors are highly effective in preventing transmission of secondary noises due to scratching and so on, and the gaps in the metal conduit wholly or largely prevent resonant vibration of the conduit due to the sounds which it transmits.

Con-

conduits. What I claim is: 1. A phonograph comprising a sound box,

a tone arm, a horn, a tube-between the horn and the tone arm, resilient means connecting the sound box with one end of the tone arm, resilient meansconnecting the other end of the tone arm with one end of the tube, and resilient means connecting the other end of the tube with the horn.

2. A phonograph comprising a cabinet, a sound box, a tone arm, a horn, a U-shaped tube between the horn and the tone arm, resilient means comiecting the sound box with one end of the tone arm, resilient means connecting the other end of the tone arm with one end of the U-shaped tube, resilient means connecting the other end of the tube with they respectively connect. The ball of the the horn, and resilient means connecting the mouth ofthe horn with the cabinet.

In testimony whereof I afiix m signature.

ERNST F KING. 

